Image fusion-based recurrence patterns and dosimetry after concurrent chemoradiotherapy for thoracic esophageal squamous cell carcinoma / 中华放射医学与防护杂志

ABSTRACT

Objective:To analyze the local recurrence patterns after concurrent chemoradiotherapy (CCRT) for thoracic esophageal squamous cell carcinoma (ESCC) through image fusion, and to explore the risk factors of local recurrence and its relationships with dosimetric indices.Methods:A retrospective analysis was conducted for 209 thoracic ESCC patients who received radical CCRT in Fourth Hospital of Hebei Medical University during 2016-2019. For the patients diagnosed as the local recurrence of esophageal lesions, their CT images were fused with the original planning CT images using image registration software to identify the recurrence sites. Through 1∶1 propensity score matching (PSM) of the clinal data of patients with local recurrence (the recurrence group, nbefore = 81, nafter = 62) and those without local recurrence (the recurrence-free group, nbefore = 128, nafter=62), the dose and volume parameters of the treatment plans for the two groups were compared. Univariate and multivariate analyses were conducted using the Kaplan-Meier method and the Cox regression model to analyze the factors affecting the overall survival (OS), progression-free survival (PFS), and recurrence-free survival (RFS). Results:All patients had 1-, 3-, and 5-year OS rates of 80.9%, 42.6%, and 33.0%, respectively, 1-, 3-, and 5-year PFS rates of 67.9%, 34.0%, and 27.9%, respectively, and 1-, 3-, and 5-year RFS rates of 71.3%, 39.2%, and 30.5%, respectively. T stage, N stage, and radiation dose were independent prognostic factors for the OS, PFS, and RFS ( HR = 1.42-1.87, P < 0.05) of the patients, respectively. Among 68 patients with local recurrence, 62 cases (91.2%) suffered recurrence within the gross tumor volume (GTV). The dose and volume parameters of patients with local recurrence, such as GTV- D95%, clinical target volume (CTV)- D95%, GTV- D50%, CTV- D50%, and planning target volume (PTV)- D50%, GTV- V60, CTV- V60, and PTV- V60, were significantly lower than those of patients free from the local recurrence ( t=1.90-2.15, P < 0.05). Conclusions:Local recurrence of patients with thoracic ESCC after radical CCRT occurs mainly within the GTV. Increasing radiation doses may contribute to their survival benefits. The D50% for each target volume in the radiotherapy plan may be related to local recurrence, and it is necessary to conduct further research.